


Electric Tonight

by DoreyG



Category: The Avengers (2012), Thor (2011)
Genre: Again sort of, Alternate Universe - Modern Setting, F/M, Genderswap, I'm saying sort of a lot in these, Loki is fond of avoiding emotions, Loki is seventeen and Thor is eighteen, Pseudo-Incest, The UK, Well Door!sex, Yes Loki is a teenage girl in this, alternate universe - secondary school, the underage isn't even technically underage where this is vaguely set, wall!sex, well sort of
Language: English
Status: Completed
Published: 2012-06-11
Updated: 2012-06-11
Packaged: 2017-11-07 12:45:35
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,813
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/431363
Author URL: https://archiveofourown.org/users/DoreyG/pseuds/DoreyG
Summary: <blockquote class="userstuff">
              <p>Okay, so, <i>um</i>: He doesn’t <i>actually</i> remember when he started sleeping with his adopted sister (his adopted <i>little</i> sister, on days when he’s feeling particularly miserable). He’s pretty sure that it happened after her sixteenth birthday, one year and two months ago, but other than that… Well. He only knows that it <i>happened</i>, and has <i>kept</i> happening ever since.</p>
            </blockquote>





	Electric Tonight

**Author's Note:**

> Vaguely (very vaguely) set in the UK. Loki is seventeen, and thus a teenage girl, and Thor is eighteen.

“ _Thor_.”

Okay, so, _um_ : He doesn’t _actually_ remember when he started sleeping with his adopted sister (his adopted _little_ sister, on days when he’s feeling particularly miserable). He’s pretty sure that it happened after her sixteenth birthday, one year and two months ago, but other than that… Well. He only knows that it _happened_ , and has _kept_ happening ever since.

…Which explains why Loki is currently leaning ( _sprawling_ ) in his doorway, and favouring him with a smirk that could probably make even Mr. _Heimdall_ lose his shit and fall helplessly to his knees.

A good thing he has a bit more strength than the imaginary Mr. Heimdall.

“Loki, I’m doing _homework_.”

…A good thing he’s sitting down.

“No you’re not, Thor,” his adopted sister informs him cheerfully, swaying a little further into his room with her absurdly short skirt and hair _somehow_ tumbling gracefully out of its ponytail (‘How does she manage it?’ Sif has marveled often, over beer that they’ve stolen from her father’s secret stash ‘whenever _I_ undo my hair after school I end up looking like some disgusting swamp creature’), “You _never_ do your homework. It’s one of your fatal flaws.”

“I do too!” He protests weakly, _maybe_ a touch fascinated by those long legs under that short skirt “…Besides, I thought that I already had a fatal flaw.”

“You’re _allowed_ to have multiple fatal flaws, Thor,” those long legs that are moving closer to him, and he _swears_ that Loki is doing it on purpose (the showing off her legs, not just the walking because that’s quite _obviously_ on purpose), “it’s unavoidable in your case, I’m afraid.”

“…Hey!” He briefly considers rising to his feet, remembers (oh, so he can remember _that_ but not the first time Loki crept into his room at night and straddled him) _why_ that’d be a bad idea just before he makes a fool of himself, “that’s unfair, sister.”

“But true,” though he’s probably already made a fool of himself, judging by her _actually audible_ smirk “…If you aren’t doing your homework then you’re free to do other things, yes?”

…He _huffs_ , for he’s never been entirely fond of being made the fool-

“Thor…”

-But soon smiles, for you have to learn to _take_ such things when you have an adopted sister (an undefined thing) such as Loki, “what do you want, sister?”

“For you to stop calling me sister, _Thor_ : it’s faintly disturbing in this situation,” her legs come closer still… He drags his gaze from her legs, up to her smirking (half smiling) eyes, “and for you to _strip_. You look so, _so_ much prettier when you’re naked.”

“ _Loki_!” he hisses, that _actual_ smile on her lips almost convincing him to obey even as he thinks that he should be slamming his head into the desk, “the door is open-“

“Your father is out.”

“Loki…”

“And mother too,” that _actual_ smile fades a little, he finds himself rising and hurrying a step forwards _just_ to coax it back into life, “nobody will hear us, Thor. Unless you start screaming again and I _trust_ that you’ve learnt after last time.”

He _shudders_ at the very mention of last time.

Takes another step, “they might come back-“ 

“They won’t.”

Another, “they _might_ -“

“They _won’t_.”

_Another_ -

“ _Fine_ ,” and Loki steps back from him, kicks the door shut with the heel of her non-regulation boot (that she somehow gets away with, _every_ single time) and leans grumpily back against it, “ _better_ , my paranoid Thor who can’t take yes for an answer?”

…That _actual_ smile is still fading, despite his best efforts.

“I just don’t want you to get hurt,” and he has to _run_ those final few steps towards her, gather her slim (verging on bony) body into his arms and hold her there so tightly that he might _never_ have to let go, “that’s _all_ , si- Loki. Maybe one day we can move to some far distant city and live as husband and wife, but _until_ then-“

She elbows him in the stomach.

She _elbows him in the stomach_. And when he can finally look up again, when he’s finally got his breath back for Loki’s elbows are _painful_ …

She’s laughing – loud and free and with that _actual_ smile spreading gleefully across her face, “you’re a fool, my dearest Thor.”

…He pouts at her, still with a hand on his poor stomach.

“But an adorable one,” and she, _stunningly_ , relents. Wraps her long arms around his neck, slides her talented fingers into his hair and arches shamelessly up into him, “with nice enough eyes. And a nice enough smile. And nice enough _lips_ , I suppose.” 

And _he_ -

…He relents in turn. Gathers her properly back into his arms, with the slightest wince which she _giggles_ at, and delivers his very sweetest kiss – the one which he saves for her and only her, the one that she always seems to _melt_ at like she just can’t help herself.

The kiss remains chaste, well: as chaste as they can _get_ , for only a minute before she starts clawing at his shoulders – demanding more in the way that only Loki can.

She’s always been tall for a woman, almost able to meet his eyes despite him being _way_ over six foot, and yet she’s also always been easy enough to lift (when she wants it, the last time she didn’t want it he ended up unable to play football for _half a year_ ): he hitches his hands under her thighs, under her absurdly short skirt. Waits for her pleased rumble against his lips before hiking her up the door and allowing her to wrap those long legs around his waist.

They kiss for another minute in this new position: deep, slow, with tongues moving against each other and bodies slowly swaying…

Before Loki gets impatient _again_ , and _digs her nails into the back of his neck_.

“ _Fuck_ -!”

“Please tell me that you have condoms in here,” she simply ignores him, _and_ ignores the way that her nails are still slowly tearing skin off the back of his neck, “and that I won’t have to wait against this door _forever_ while you clomp your way to the bathroom and have a good flail.”

…It occurs to him to take offence at the ‘clomping.’

But, then, if he hasn’t taken offence at the _loss of half of his neck_ he has no business taking offence to anything else. Especially when condoms are being mentioned. Especially when Loki is looking at him through her eyelashes and somehow managing to make it look sexy. _Especially_ when getting laid is quite obviously at stake.

So he, none too gently, lowers his adopted sister back to the floor.

And, none too regally, _scrambles_ over to his recently vacated desk: tearing the chair aside, ripping the second drawer open, tossing aside pens and paper clips and one incredibly mysterious sock that he’ll probably end up blaming Loki for once his brain has slipped back inside his head…

_Ah_.

When he gets back to Loki, fumbling desperately with the wrapper all the way, it’s to find that she’s already eased her underwear down her legs and flipped her skirt up even higher. She stares at him, still from under her dark eyelashes, reaches for his belt almost _urgently_.

(…Not that she’d ever admit it.)

Between the both of them (well, _mainly_ Loki with her habit of sharply slapping his oversized fingers aside) they get his belt undone, his jeans thrown across the floor and his briefs following soon after. His shirt, somehow, also ends up on the floor in the fray – he supposes that she’s always liked to see his bare chest.

_Always_ …

Loki’s eyes are concealed as she rolls the condom on, her dark hair fully free now and tumbling around her face in chaotic waves, “ready?”

“Ready,” he confirms, on a breathless choke, and lifts her up again – waiting for her hands on his shoulders and her legs around his thighs and her very slightest nod before he _dares_ to slowly push in.

And-

… _Fuck_.

He’ll never get used to being inside Loki, no matter how many times he may have done it (and he has _no_ chance of remembering as he buries himself in as far as he can go). The heat, the tightness, the way her eyes flutter shut when he finally has to grip her waist at the sheer _sensation_. The darkness of her hair as it tumbles around her face, the way her chest hitches, the way she gnaws at her lip when he brushes their mouths together. It _all_ combines into a beautiful kind of perfection that he couldn’t drag himself away from if he tried for a million years.

“Move, you idiot, _move_!”

…Not that he’d ever want to.

For Loki, his adopted little sister and he doesn’t even _care_ , is _spellbinding_ as he obeys: tilted right back against the door, her throat working around choked back moans, her legs _clenching_ around his thighs.

And Loki, _his_ adopted sister, is even more enchanting when she opens her eyes: starts digging in her nails again, _growling_ , turning the dazed presses of his mouth into proper kisses: fast and sloppy and like she just can’t _restrain_ herself with him inside her.

And Loki, _his_ Loki, is downright _captivating_ as he bends to hit that perfect spot: as she screeches, and whines, and _begs_ in a high babble. Digs her nails in so hard that she practically draws _blood_ , tightens her thighs and bites at his mouth like she can claw her way inside him. Urges him faster and faster and _faster_ -

And Loki, _his_ , is beautiful.

Is beautiful.

Is _beautiful_ -

As she comes, narrowly avoiding braining herself against the rough wood of the door and wouldn’t _that_ be something to explain to father. And as he follows a second after, groaning and shuddering and barely managing to keep himself upright.

…They stay like that for a second. The sweat cooling slowly between them, their mouths lazily moving together in the afterglow, her hands easing from his shoulders with a slow stroke almost like an apology.

Before that stroke turns into a brisk shove.

And he immediately lets her down, _gently_ lowering her to the ground as she eases her skirt back down her thighs and strokes down her hair. Looking, within but moments, like she’s never been pinned up against any doors or wrapped her legs around _any_ adopted brothers.

They stare at each other for another second.

“I love you,” he blurts, not daring to reach out again as she does up the top button of her shirt and draws herself to her full height.

…She doesn’t look at him for a long few seconds before she replies, and even then she manages to duck her head and cover her eyes, “how long before you’re ready to go again?”


End file.
